The present invention generally relates to treating sponge material to impart flexibility to the sponge material and, more particularly, to mechanically treat a rigid absorbent compressed dry sponge material to impart flexibility to the material allowing it to be easily inserted into a wound or other cavity.
A common means for mechanically imparting flexibility to sponge and other absorbent materials has been to apply variable compression to the material so that different points within the absorbent material receive little or no compression while other points receive significant or complete compression.
The method of rippling an absorbent material to provide a flexibility or softness is well known in the art. In U.S. Pat. No. 4,559,050 a non-woven web of synthetic wet resilient fibers is microcorrugated to provide a Taber stiffness value of about 25 or less. The microcorrugating process consists of passing the web through fluted intermeshing rolls having sufficient pressure to fracture and form cross-directional hinge lines. The lines found in the fibrous web product are in the machine direction thus providing hinge lines in the machine direction. The microcorrugations in the fibrous web result in a softness and flexibility imparted to an otherwise stiff material without a substantial loss of tensile strength. The fibrous web can be formed from synthetic staple fibers such as polyethylene, polypropylene, polyester, nylon, bicomponent fibers and the like which can be formed into products such as incontinence pads and wound dressings. A mechanical working of the fibers through microcorrugation hinge lines is shown to reduce stiffness in at least one direction without any significant stretching.
A rippling or creping of a surgical dressing is shown by U.S. Pat. No. 3,888,248. The surgical dressing is constructed of an absorbent core which may be creped up to 50% using conventional techniques. The finished product is soft, has greater absorption capacity than gauze and is highly resistant to passing adsorbed fluids back into a wound. Rippling is also disclosed in Canadian Patent Number 974,107 issued on Sep. 25, 1975. In this patent, an elongated sheet of non-woven, randomly arranged, intermingled, short cellulosic fibers and longer reinforcing synthetic fibers are formed into a sheet having an embossed pattern for enhancing the flexibility, absorptive rate and absorptive capacity characteristics of the sheet. The pattern is defined by a plurality of ridges and valleys extending over the entire surface of the sheet with a density of the sheet in the region of the valleys being greater than the density of the sheet in the region of the ridges. U.S. Pat. No. 4,500,585 discloses creping of a non-woven sheet of absorbent composition to make articles which can readily absorb aqueous solutions such as blood, urine and other body exudates.
Similarly, U.S. Pat. No. 5,149,332 discloses an absorbent product which is longitudinally compressed or microcreped to produce microroundulations by compressing the web in its own plane in the direction of its length by compressive forces exerted substantially parallel to a longitudinal direction of the material. The material can also be confined in a small dimension treatment cavity to produce microroundulations. The product is envisioned to be used as superabsorbent assemblages, menstrual tampons, pads such as bandages, compresses, rolls and the like and liquid distributing articles. The product has at least 10 microroundulation per inch in the layer in the direction of treatment.
The use of corrugated materials for medical devices is shown in U.S. Pat. No. 4,608,046 in which a corrugated sheet of alternating ridges and grooves allows ease in rolling or folding the sheet for use as an urinary aid for females by which they may urinate in a standing position.
Embossing to provide various designs is shown in U.S. Pat. No. 3,977,406. In this patent, medical sponges of texturized polyurethane foams are embossed in a pattern composed of a series of continuous lines no more than about 1 inch apart, each line of the design terminating at the edge of a foam sheet and intersecting another line in any direction. The embossed lines are sectioned to flow in a multitude of directions completely and unbrokenly across the sheet allowing the sheet to retain its new folded identify rather than return to its old sheet form. Examples of suitable patterns which may be embossed on the polyurethane foam include squares, rectangles, diamonds, triangles, polygons as well as random non-geometric shaped and designs. The embossed foam can be folded or otherwise compacted for medical usage in a body cavity.
Medical sponges and dressings are used to absorb bodily fluids as blood, serum, spinal fluid, tissue fluid, urine, sweat, bile juice, digestive juices and other fluids. Because the sponge material is difficult to place in human body cavities after it has absorbed fluid and since pre-wetting may decrease the amount of fluid that can be adsorbed, many absorbent sponges and dressing are placed in human body cavities in a dry compressed form.
The reason for mechanical treatment of such dry compressed materials is that the material when compressed into rigid form can cause tissue damage during insertion when encountering an obstacle such as a bony or tissue spur or cavity curve. Furthermore, such rigid sponges can be limited as to depth of insertion and generally do not conform to the wound cavity or body cavity. Foamed absorbent sponges are treated in the aforenoted mechanical manner to allow additional flexibility for packing in cavities, wounds or against organs for maximum absorption.
The present invention utilizes methods which impart flexibility to dry rigid absorbent sponge materials through a number of mechanical sponge treatment techniques to provide a number of novel sponge devices.